<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Markdown</title>
</head>
<style>
    .container {
        width: 1000px;
        height: 800px;
        border: 1px solid #ddd;
        display: flex;
    }
    .container-pre{
        width: 50%;
        height: 800px;
        border: 1px solid #ddd;
        font-size: 50px;
    }
    pre{
        white-space: pre-wrap;
        word-wrap: break-word;
        padding: 10px;
        margin: 0;
        box-sizing: border-box;
    }
    .preview {
        background-color: #fafbfc;
        border-left: 2px solid #ddd;
    }
</style>
<body>
    <div id="container" class="container">
        <pre id="container-pre" class="container-pre" contenteditable="true"></pre>
    </div>
</body>
</html>